c ++ 11在信号处理程序中使用条件变量 [英] c++11 use condition variable in signal handler

问题描述

使用std::condition_variable::notify_one<是否安全/code> 在信号处理程序中?示例:

Is it safe to use std::condition_variable::notify_one in signal handler? Example:

enum State {
  DoNot,
  Do,
};
State state;
std::mutex mutex;

// worker thread
std::thread th = std::thread([]()
{
    std::unique_lock<std::mutex> lc(mutex);
    cv.wait(lc, []() { return state; });
});

//signal handler
void handler(int sig)
{
    if (sig == SOME_SIG)
    {
        std::unique_lock<std::mutex> lc(mutex);
        state = Do;
        cv.notify_one();
    }
}

推荐答案

C++14 标准草案 N4296 说:

A C++14 draft standard N4296 says:

[support.runtime]/10 C 和 C++ 语言的公共子集由所有声明、定义和表达式组成它可能出现在格式良好的 C++ 程序中，也可能出现在符合标准的 C 程序中.POF(普通的旧函数")是一个只使用来自这个公共子集的特征的函数，并且不直接或间接使用任何不是 POF 的函数，除了它可能使用普通的无锁原子操作......行为任何在 C++ 程序中用作信号处理程序的 POF 以外的函数是实现定义的.

[support.runtime]/10 The common subset of the C and C++ languages consists of all declarations, definitions, and expressions that may appear in a well formed C++ program and also in a conforming C program. A POF ("plain old function") is a function that uses only features from this common subset, and that does not directly or indirectly use any function that is not a POF, except that it may use plain lock-free atomic operations... The behavior of any function other than a POF used as a signal handler in a C++ program is implementation-defined.

强调我的.

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